Objective: MI is a major cause of mortality worldwide. Inflammation plays a key role in the pathology of MI. Teriflunomide (TERI), an orally active Dihydroorotate Dehydrogenase inhibitor, inhibits de novo pyrimidine synthesis. It decreases production of inflammatory cytokines and suppresses the activity and proliferation of activated lymphocytes. Hypothesis: TERI, on account of its potent anti-inflammatory activity may attenuate Isoproterenol induced cardiac injury in rats. Thus, we aimed to investigate the cardio-protective effect of Teriflunomide in isoproterenol (Iso) induced myocardial infarction. Design and method: To induce myocardial infarction in rats, we administered 2 doses of Isoproterenol (85 mg/kg/day, s.c.) on days 13th and 14th, at an interval of 24 hours. Male albino Wistar rats were divided into 5 groups (n = 6); namely normal control, isoproterenol control, Teriflunomide groups to receive saline, isoproterenol, or Teriflunomide (1, 3 or 5 mg/kg/day, p.o.) for 14 days. On the 15th day, rats were anaesthetized and right coronary artery was cannulated to record hemodynamic parameters. Blood sample was collected via cardiac puncture, heart was excised and preserved for analysis of biochemical, histopathological and ultrastructural studies. Results: Isoproterenol administration to rats resulted in induction of MI with impairment of hemodynamic parameters. Teriflunomide pretreatment showed significantly improved hemodynamic (systolic, diastolic and mean blood pressures) and cardiac function parameters (normalized ± LV dP/dt and LVEDP) with reduction in the levels of cardiac injury markers (CK-MB, LDH). Further, Teriflunomide significantly reduced oxidative stress (enhanced levels of SOD, GSH, decreased MDA levels) and inflammation (reduced levels of TNF-alpha, IL-6), led to inhibition of active JNK and p38 proteins and activation of ERK1/2, a pro-survival kinase. Furthermore, it also ameliorated apoptosis by reducing the expression of pro-apoptotic proteins (Bax and Caspase-3) and increased expression of Bcl-2, an anti-apoptotic marker. In addition, pretreatment with Teriflunomide preserved morphological and ultra-structural architecture of the myocardium as seen by H & E staining and electron microscopy. Conclusions: Teriflunomide at 1 mg/kg offered cardio-protection by improving hemodynamic profile, oxidative stress profile, reduced inflammation, normalization of myocardial architecture.
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